1. Field of the Invention
The invention relates to a fastening plate for the fastening of a fitting, e.g. a hinge arm, to a supporting wall.
2. Description of the Related Art
In a fastening plate known from DE 86 20 441 comprising a bottom plate and a top plate covering it at least partially, the bottom plate is provided on its bottom side with integral dowels whose boreholes align with the boreholes of the bottom plate. This aspect is advantageous, in particular in the case where the fastening plate is supplied already pre-mounted to the hinge arm connected to the door, as the door can then already be hung on the supporting wall by inserting the dowels into the pre-drilled fastening holes before the fastening screws are fully screwed in and before the dowels are thereby spread. If such fastening plates are intended to be mounted to opposite sides of a supporting wall in a twin fixture, their mounting is only possible if the supporting wall is so thick that the fastening screws or the dowels can be inserted in the aligned boreholes of the supporting wall in such a way that they do not impede one another. However, such a connection is usually unsatisfactory.
In a fastening plate known from DE 297 13 595 U, the boreholes or dowels of the bottom plate and the oblong holes, which are penetrated by fastening screws, of the top plate are disposed opposite each other at equal distances to the transverse axis of the top plate running through the wing-like projections so that two fastening plates provided with corresponding boreholes disposed in pairs next to each other for the fastening screws can be mounted in a twin fixture on opposite sides of a supporting wall. However, this aspect requires a special and complex preparation of the supporting wall which does not correspond to the standardised borehole distribution in the supporting wall.
It is therefore the object of the present invention to provide fastening plates of the type first described which can initially provisionally be pre-mounted and then fastened in a superposable twin fixture on opposite sides of a thin supporting wall without having to make any special preparations therefor.
This object is solved in accordance with the invention on the basis of a fastening plate in which, on the one hand, a spreading dowel is integrally formed in a homogeneous material to the borehole of the bottom plate, said dowel having a shorter length than usual, and, on the other hand, possesses a borehole partially encompassed by base-like elevations and having a pre-mounted screw which is also shorter, but which has a larger diameter so that it cuts directly into the walls of the boreholes pre-drilled into the supporting wall after mounting.
The fastening plate in accordance with the invention can be pre-mounted superposably in a twin fixture on opposite sides of a supporting wall because the dowels can be inserted into the pre-drilled fastening holes with a low driving fit. If then only those fastening screws aligned therewith are fully screwed in, the spread of the dowels is not yet sufficient to ensure a good fastening as the length of both the dowels and the spreading screws are too small in size. In the fastening plate in accordance with the invention, however, the second fastening screw is designed in a comparatively larger diameter so that it can also ensure a better retaining force even in limited length. Such screws can, for example, be designed as xe2x80x9cEuro screwsxe2x80x9d, i.e. as screws possessing a thread diameter of 6.4 mm.
Accordingly, both boreholes of the bottom plate can be encompassed in a known manner by the base-like elevations which serve as guidance in the adjustment of the top plate with respect to the bottom plates. For the better retention and alignment of the screws with a larger diameter, the top plate can be provided with short tongues bent down at the side at the edges of the oblong hole. In this way, both plates can be properly pre-mounted on top of each other as the threads cut partially both into the tongues and the base-like elevations.
As already known from DE 297 13 595 U, in accordance with another advantageous aspect, an elevation designed as a tenon can be disposed in the end region of the bottom plate provided with the dowel, which elevation engages an oblong hole of the top plate parallel to the oblong holes penetrated by the fastening screws for guidance and centration.
The fastening plates in accordance with the invention can also be mountable in the provided boreholes of the supporting wall after being turned through 180xc2x0 so that they are suitable for both left and right fixtures.
A further solution to the object defined above is given by a fastening plate in which, in a region of the bottom plate which lies below the elongated part of the top plate in the mounted state, at least one dowel-like extension or two bent tongue-like extensions are formed. With this design, it is possible to provide pre-mounted screws with a comparatively larger diameter (xe2x80x9cEuro screwsxe2x80x9d with thread diameters of 6.4 mm) in both screw holes.
According to further aspects of this solution two dowels can be formed at a distance to one another on the bottom plate. Furthermore, on the bottom platesxe2x80x94in the region of the edges of the fastening boreholesxe2x80x94tongues pointing downwards can be formed on integrally which serve the centration and correct alignment of the fastening plate. When the screws are being screwed in, these tongues are deformed by the screws. If bent, tongue-like extensions are provided, their edges may have a slightly slanting course with respect to their symmetric line. In this way, these bent tongues, which replace the dowels alternatively provided, ensure a provisional retention in the boreholes of the furniture panel. In addition, the boreholes in the bottom plate for the pre-mounted fastening screws can be designed hexagonally. By cutting at six points, a better centration or alignment of the fastening screws can be ensured.